Loading...
HomeMy WebLinkAboutGEO-Tech Review BLD2000-01330 - BLD Engineering / Geo-tech Reports - 2/14/2000 MARTIG ENGINEERING P.O. Box 11850 Olympia, WA 98508-1850 (360) 754-9687 February 14, 2000 Mason County Department of Community Development 426 W. Cedar P.O. Box 578 Shelton, WA 98584 Attn: Randy Neff, Planner Re: Geo-Tech Assess ment/Report Compliance Report for: * Owner: Nora Boles 16851 31 St Ave South Seattle, WA 98188 * Site Location: Spruce Street, Union, Mason County, Washington; Lots 19 & 20 of Block 20, Union-Grays Harbor & UCRR Add.; *Tax Parcel No.: 32232 52 20019; * Mason County: Sec 32, Township 22 N, Range 3 W; & * PROPOSED SINGLE FAMILY RESIDENSE. Dear Mr. Neff: I, Kenneth W. Martig, Jr., PE, of Martig Engineering have completed my engineering investigations regarding the Geotechnical Assessment/Report requirements associated with the above referenced property overlooking Hood Canal, looking north. This Geotechnical Assessment/Report letter report presents our findings. In summary, the measured slope of the property is16.7% and no drainage, geological, or slope condition of instability was found that would prevent the approval of this Single Family Residential Development as proposed. INVESTIGATION SOURCES 1. Forest Practice Base Map (Sec. 22, T 22 N., R. 03 W.,), Attach. #1; 2. Elevation Section View of Site (Section A-A, taken from Attach. #1), Attach. #2; 3. Stereo Photographs dated 8/10/97 (photo 39-80-70 copy), Attach. #3; 1 4. USGS 7.5 Minute Quadrangle Topographic Map (Union), Attach. #4; 5. 1980 DNR Coastal Zone Atlas, Attach. #5; 6. Slope stability, USGS/Carson MAP 1-853F, Attach. #6; 7. Ken Martig, Jr., PE February 4, 2000 Field Trip Site Investigation; & 8. Soils Survey, Mason County Washington, Series 1951, No. 9. PROPOSED ACTION The proposed action at this site is the development of one private single family residence. Existing Union public roads will be used for access to the residence building site which is to be located immediately north of Spruce Street on Lots 19 & 20 of Block 20 of the Union-Grays Harbor & UCRR Addition (see Section A-A, Attachments #1 & #2). An On-Site Septic System will be used to serve the proposed single family residence, approval being processed. An existing community water system will supply domestic water to the residence. LAND DEVELOPMENT PLAN The Nora Boles plans to develop a private single family residence on this property. INVESTIGATION DISCUSSION Attachments #1 & #2 show the location and elevation view of the property. The slope of the proposed building site lot was found to be 16.7% by survey measurement. Attachment#3 shows the site on a 1"=500' enlarged Aerial Photograph (8/10/97). Attachment#4 shows the site on the Union USGS Quadrangle Map. Attachments #5 & #6 show the property's location on the two Slope Stability maps, the Coastal Zone Atlas Map & the USGS/Carson MAP 1-853F. As can be seen, the Boles site lies on the boundary between land designated as stable and land that could become unstable by development activity. Because these maps present a broad-brush representation of stability/instability and since the northerly portion of the Boles property is designated "stable", a field survey of the property was conducted to identify the actual slope of the property. 2 Martig Engineering found that the site slope is 16.7%, just slightly above the 15.0% that is deemed to be stable. All follow-up research and investigations showed that this land is stable and will not become unstable if a single-family residence is developed here. A review of the 8/10/97 DNR stereo aerial photographs with stereo glasses confirmed a stable terrain, no slide zones, wet areas or other signs of instability were visible. The Mason County Soil Survey showed that the soils are an Alderwood gravely, sandy, loam with its till layer approximately 24" to 32" deep. Numerous single-family residences have been developed on lots within this Union housing development. No visible signs of slope instability were found. DRAINAGE AND EROSION CONTROL Very little groundwater/interflow or surface water runoff is tributary to the Boles site. Most upgradient runoff drains through a draw well west of the site. Spruce Street has roadside ditches that halt runoff from south to north. Fir Street below also has roadside ditches to collect and convey runoff. CONCLUSION The geological soil and slope conditions at the site of the proposed residence are stable and compatible with the proposal to place a private single family residence at this site. Therefore, no adverse impact on the hillside should be experienced if this proposed residential development is allowed, and properly permitted by Mason County. This Geotechnical Assessme eport Is Certified by: 1 L�n�eth artig, Jr., P Attachments: Six Attachments as listed above. �, 2 9�F ISTEP�a�?� S`s�ONAIL Ea �fRES 1�9- 6 Z- 3 f ■ �~fir'-.. -y:� .. f +'/ ,.yam. ., 'r�.xK,• _, - Ig4o off fL co ti tr \ ` Skokomish Indiar • At�acl�,w.e. - 4 Bm9 .� 1 M ice.% :.r.vl•:1ii1; BM Io ,I , •3 ( 1 ' I 1� GOO ■ 0 At ■ rr 11n 1 �� J • ■ jj lip • • Tr - - - ::_ i . �qr Ii��, �` � 1 e r � ,( % Orfd ��'` \ � j� ;� j� • u'h 5 t /•fin {DAISY OAQ 1 I vFr. - c ; J 30 MANIA ITAq 8 q ' l a ter T Fl FOR EST PRACT I CE BAS E MAP TOWNSHIP 22 NORTH , R A N C F 03 WEST ( W . N ) SECTION 32 APPLICATION r 0 EB Q — 7 71 I Z40 3 z o � 4 I P ht I v _ ui�i 70 / 87 j J ; A I z r �200- 2000 �3000 4000 50001,.E 6000 r am 7' IIUC 10 MAP DATE Fdwy 25, 1997 CONTOUR INTERVAL : 40 Feet LEGEND : See Instructions NAD 21 DISCLAIMER : See legend water/wetlands includina their lnratinn •nn rleee mn.. he inrnr%rerrtly diianlavari nrr not •hOwn r u da w f 9 P � A. S�,�ru�c Q n D ,n6n1e5 k J O � 3Da p zoo 4-00 goo goo t000 Zoo 1400 boa Se��tti� � - /� �tY•a.I �1,�o-�-o � �10117 rr � wwr 71 t"',O"A VP lb Rw re 04 * r , r � `d err 1�� r •.r L t ;�Y' - i �C� Y l � a •, •r.'i �j. AAAFF i3��ti ,,�• I i'I swh �, 1 Pt ,' , Slope. S A-0, !AS 6.S Ga►vso K + x �n �►P s- 85 3 F iiiiiiiijillillIllIll11111111111111111 ..r- A.AL � 4 * (S41106bla V►M.Lev 1'4 r �. N Ga %�oL� f \ MASON COUNTY PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER Shelton,Washington 98594 DATE: Nov. 13''', 2000 INTER-DEPARTMENTAL COMMUNICATIONS TO: Shandra O'Haleck, DCD - Planner FROM: Alan A. Tahja, P/W - Co. Hydr. Engr. DCD/Planning WO# 00-0096 SUBJ: Geo-Tech Assessment Review NAME: Nora Boles 2 Union BLD2000-01330 Shandra, A geotechnical assessment prepared for the proposed Nora Boles residence at Union has been received and reviewed by Public Works. The report conforms to standards of sound engineering principles and practices and conforms to the requirements of DCD for geotechnical assessment reporting. If the site plan included in the Building Permit Application is considered a part of the geotechnical investigation,the assessment could be entertained as a geotechnical report under Mason County policy guidelines. The assessment indicates that the measured slope on the property is 16.7%,which seems reasonable to assume would oily require an assessment to be prepared, assuming there are no surface indications of instabil In the absence of any additional information indicating instability,the asssment may be considered acceptable, and there appears to be no justification for requiring additional site investigation or reporting. If the engineer who authored the assessment had included a site plan containing the information required in Mason County policies(Yando's 10/6/98 Memo),this assessment could be entertained as a geotechnical report. With these issues in mind,I feel this assessment should be accepted and the project allowed to proceed through permit processing. Please feel free to contact me at County extension 461 if you have any questions regarding these comments, or if you feel any features need further discussion or attention. 4erely, lan A. Tahj File: H:\WP\GEO\ASESMNTS\Boles.doc 1 WORK ORDER - PUBLIC WORKS DEPT. py Date.* _1 %(o/0 O �;�j 'j�j�S (q Work Order PEIT a : ber: Number. Requested by: Authorized by: ,,^ Date: Type of Work: C�� -I,—C -n_ v-c Li. CHARGE TO: NAME (4 n AGENCY/COMPANY 14 BILLING ADDRESS `<:j PHONE L) Pub. Works Person In Charge: (C) Pmject Time Line: (from -to dates) TO Project Start date: 1 13 Esdmated Rish Date: APProxiffate hors: ESTIMATED TOTAL SS: 3Z, COST ESTIMATE (D) Elyse I E91 !fours Subt4S31 Frimn% TOTAL$ SJ� BAIE TOTAL n EQUIPMENT USED: MATERIAL USED: �„>i:;?.L`�-- >w1:c{,•:..�.;.y.-?<:<''.. :"':f:::.::.�� '.;. :� :3L:::^).C'a'ry':Y%.-.w...::�'.::,;,_•r":."K:A:J.>ZYK -�iR4.a.AWDe.oF-hlfa-�+fdl..r..rk+w�Y•.JGw.�we:eL.T�Y.4cadawfaava. .., - ..:..-:-.:;..,::-:.`^'.........0 ..:<aea.-.w:-;:c.:..;;�..w�,c.c::::u>a�6Ra:-. �la.,?-�[ �.taloa:.Z•-.�(�fa (F) Actual Cost S BARS: PROD : DATE Eirployea Y Nwm I:B3Lti Flours SyNoW Ednot,% TOTAL$ EQUIPMENT USED: Date V11-ft Rate TOTAL SS MATERIAL USED: TOTAL ALL (G) BILLED DATE INV 0 PAID DATE RECIt CKX